re: trouble shooting GPUSB

Questions about hardware and software obtained directly from Shoestring Astronomy
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Max Oelschlaeger
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re: trouble shooting GPUSB

Post by Max Oelschlaeger » Sun Mar 18, 2007 12:33 pm

I’m trying to use PHD Guiding with the GPUSB plus the Shoestring ST4 cable (recently purchased) in combination with a Meade DSI as a guide camera only.

To date I’ve not been successful in achieving autoguiding, which is surprising, given the large number of people who have successfully autoguided with such a system. Perhaps it’s user error? Always check the loose nut at the end of scope, eh?

Here are the variables. I’ve tried to achieve control with two different PCs (fully upgraded XP OS) using two different versions of PHD (1.4 and 1.5 pre 2) on two different mounts with ST4 autoguide ports (a CGE and a CG5 goto).

I have used the GPUSB test software in all configurations (CGE w/ computer 1 attached via GPUSB and cable to autoguide port, CGE w/ computer 2 attached via GPUSB and cable to autoguide port, ditto with the CG5). The test software can change the LED light color and also turn the LED off and on. However, the directional commands produce no movement under any configuration (double-checked with a reticle EP to make sure that I am not missing any micro-metric subtle movement).

(Incidental data: both computers successfully communicate with the mounts and/or other hardware as appropriate. For example, I can use ImagesPlus in a two cable hookup to control my Canon DSLR. I can use the Sky to control either mount. I can image guide stars with the DSI through PHD.)

Advice? Am I missing something? The only remaining trouble shooting idea I can think of is a voltage test. Is there some way I can check the pins for a small pulse on the GPUSB and then, if necessary, on the cable itself? The question would be which pins and what voltage range.

Many thanks.
Max
Max

dpanderson
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Post by dpanderson » Mon Mar 19, 2007 6:44 pm

Max,

It sounds like you have done an excellent job of troubleshooting to this point. Using a multimeter, here is what you can do to see if the signals are coming out of the GPUSB properly.

Connect the GPUSB to the PC, and the GPUSB to your mount using the RJ-12 cable. Open up the GPUSBCheck software, and tell it to connect. Make sure you can control the LED. Then, put the multimeter in DC voltage mode and do the following. It is convenient to probe the pins where the RJ-12 connector bumps up out of the GPUSB. All measurements are made using the positive probe of the multimeter with the negative probe touching pin 2.

1) With no direction buttons pushed on GPUSBCheck, check that the voltage on pins 3, 4, 5, and 6 are high. This will likely be around 5V, but could be around 12V, depending upon the mount.

2) Click the Dec+ button on GPUSBCheck. Pin 4 should now go low (around 0.3V) and pins 3, 5, and 6 should stay high.

3) Click the Dec- button on GPUSBCheck. Pin 5 should go low, and pins 3, 4, and 6 should be high.

4) Click the Dec- button to deassert it, then click the RA+ button. Pin 3 should go low and pins 4, 5, and 6 should be high.

5) Click the RA- button. Pin 6 should go low and pins 3, 4, and 5 should be high.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

Max Oelschlaeger
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Post by Max Oelschlaeger » Tue Mar 20, 2007 7:49 am

Doug, thanks for the information -- exactly what I needed!
I'll run the tests in the next day or two and report back.
Max
Max

meat head mike
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Trouble Shooting GPUSB

Post by meat head mike » Wed Nov 14, 2007 12:44 pm

Hello Doug,
I have followed your instructions with the Multi-Meter!
My problem is when calibrating the GPUSB with an Orion Skyview Pro Go-To Mount it wont track on the DEC shaft!
It said couldnt connect to the Dec but will track in RA only!
This is what i have from the Multi-Meter test,
#1- , pins 3-4-5 are 5volt but pin 6 is 0.5volt! low
#2- , pin 4 is 0.5volt normal, pins 3-5 are 5 volt normal, pin 6 is low at 0.5volt.
#3- , pin 5 is normal, pins 3-4 are normal but 6 is low at 0.5volt!
#4- , all pins are at normal voltage!
#5- , all pins are at normal voltage!
I was surpirsed how easy the GPUSB was to setup!
the red and green LED switch works fine!
I tried this in different USB slots on my notebook just to see if that was a problem but it was the same reading!
Thanks, Mike

dpanderson
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Post by dpanderson » Wed Nov 14, 2007 12:59 pm

John,

Does your multimeter have a "diode check" function? If so, could you try the test with no mount connected to the GPUSB as mentioned in the last post of this thread: viewtopic.php?t=117


Also, do you have any other mounts you can try it with?
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

meat head mike
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GPUSB

Post by meat head mike » Wed Nov 14, 2007 1:12 pm

Hello,
I just tried the test again with PHD Guide on and the mount tracking and all pins tested 100% as in your instructions!
Im not sure why the DEC wont track though?
is there a setting in the advancedsetup i need to change?
i dont have another mount to test on!
the last post was with the mount on but not tracking!
i am confused about the readings :-)
was this test with PHD Guide on how it should be done?
I do have backlash on the DEC shaft and not the RA shaft!
that could be a problem but the PHD Guide did try to correct for backlash!
any tips on how to correct this?, my guidescope arrives tomorrow!
but i used my main scope to test last night on a star!
Thanks, Mike

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Post by dpanderson » Wed Nov 14, 2007 1:30 pm

The test as originally posted was using only GPUSBCheck software and nothing else. Not sure why having PHD Guiding running would change anything, but at least it appears that your GPUSB is functioning properly.

Lots of users have reported calibration problems with PHD Guiding when there is backlash. The best place to get help with this would be the Stark Labs Yahoo group: http://tech.groups.yahoo.com/group/star ... -software/
Doug Anderson
Shoestring Astronomy
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meat head mike
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GPUSB Tested 100% with PHD Guide

Post by meat head mike » Wed Nov 14, 2007 2:31 pm

Hello,
Yeah i wondered if using PHD Guide made a difference which it did!
yes it looks like the GPUSB Autoguider works like it should but w/o
the PHD Guide not running the test showed bad results?
Can you recommend another Guide software..Freeware :-)
the 80mm guidescope arrived a day early so a full test tonight!
would the GPUSB Autoguider have a problem if my mount wasnt set up correctly?, maybe im tring to over work the GPUSB?
i did a drift test and adjusted Alt/Az & Latitude as needed and i do hear the R/A & DEC drives making a huming noise with the GPUSB activated!
it must be a issue with my mounts DEC shaft or my drift test wasnt right?
each mount is different but maybe you know a DEC backlash setting i can use in the advanced settings?
Thanks, Mike

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Post by dpanderson » Thu Nov 15, 2007 8:36 am

I am mystified why running PHD Guiding has any effect as well.

Guide Dog and Guidemaster are two other free programs you might try. See http://www.store.shoestringastronomy.co ... cts_gp.htm for a list of all the software we are aware of and where to get it.

If your mount/scope are not close to balanced, then the motor may not be able to drive it, but this should not keep the GPUSB from trying anyway.

Backlash settings tend to be unique to each mount, so I'm not sure what to recommend for your particular mount.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

meat head mike
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GPUSB Tested 100% with PHD Guide and Guiding is great!

Post by meat head mike » Thu Nov 15, 2007 5:28 pm

Hello,
I had everything working great last night!
the GPUSB is a must and its so easy to setup right out of the box!
i didnt need ASCOM to run the GPUSB or anything running WIN Vista!
the issue i was having was me!, bad mount setup!
but i took the extra time aligning the mount and then the autoguider did the calibration and started tracking!, i did have some back and forth motion going in some images but stacking got the trails out!
im very satisified with my GPUSB and next month plan to buy the adaptor for the Orion Accfocuser!
Thanks Shoestrings!

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Post by dpanderson » Thu Nov 15, 2007 9:13 pm

You're welcome. Glad to hear it all came together for you!
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

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